Implicit pubset assignment and release

In addition to explicit pubset assignment by the VM2000 or VM administrator, the guest system operator can assign the devices of a pubset (pubset for short) to itself (implicitly) if the requirements described below for the VM and the pubset devices are satisfied.

Requirements of the pubset devices for implicit pubset assignment

All pubset devices of a pubset which is envisaged for implicit assignment to a VM must have the ASSIGN-BY-GUEST attribute and should be assigned to precisely one assignment set. Information on assignment sets is provided in the section of the same name on "Assignment sets, implicit device assignment and release".

The pubset devices assume the ASSIGN-BY-GUEST attribute in /MODIFY-VM-DEVICE-ATTRIBUTES UNITS=*PUBSET-DEVICES(...) and in the process are assigned to a created assignment set.

As a rule, the devices of a pubset should only be assigned to one assignment set.

If a pubset was specified using /MODIFY-VM-DEVICE-ATTRIBUTES UNITS=*PUBSET-DEVICES(...), the pubres device of the pubset in the VM2000 device management is assigned the PUBRES-FOR-ATTRIBUTES attribute. The attribute is withdrawn only if the pubres device was explicitly specified in the device list in /MODIFY-VM-DEVICE-ATTRIBUTES. The attribute is retained when UNITS=*ALL / *PUBSET-DEVICES / *BY-ASSIGNMENT-SET or a device list with wildcards was specified.

A pubres device (and possibly its DRV mirror disk) with the PUBRES-FOR-ATTRIBUTES attribute is marked by the suffix (P) in the ASSIGN-SET column of the information output of /SHOW-VM-DEVICE-STATUS, e.g. *STDSET(P).

Information on whether pubset devices have the ASSIGN-BY-GUEST attribute and the assignment set to which they are assigned can be obtained using /SHOW-VM-DEVICE-STATUS.

The ASSIGN-BY-GUEST attribute can be removed from the device again using /MODIFY-VM-DEVICE-ATTRIBUTES.

Requirements of the VM for implicit pubset assignment

Each VM which to be able to implicitly assign itself pubsets must have the ASSIGN-BY-GUEST privilege for the relevant assignment sets to which the required pubset devices are assigned. This privilege can be set when the VM is initialized (see "Initializing a VM") or with /MODIFY-VM-ATTRIBUTES; the assignment sets required are then assigned to the VM.

Assignment sets for a VM can be entered in the VM definition with /CREATE- or /MODIFY-VM-DEFINITION. Detailed information can be found in the section "Working with VM definitions".

Information on whether a VM has the ASSIGN-BY-GUEST privilege and the assignment sets which are assigned to it can be obtained using /SHOW-VM-ATTRIBUTES/-RESOURCES INFORMATION=*PRIVILEGES.

/MODIFY-VM-ATTRIBUTES enables you to modify the set of assignment sets which is assigned to a VM or to remove the ASSIGN-BY-GUEST privilege from the VM.

Using /SHOW-VM-DEVICE-STATUS SELECT=*PARAMETERS(ASSIGN-BY-GUEST=*YES(SET-NAME=*BY-GUEST(GUEST=<vm-id>))) (/SHOW-VM-DEVICE-STATUS GUEST=<vm-id> for short), the devices can be ascertained which a guest system may assign itself implicitly.

The BS2000 command /SHOW-DEVICE-CONFIGURATION UNIT=*PUBSET-DEVICES(...),INFORMATION=*VM2000 provides information on the options for implicit pubset assignment to the local VM in the guest system, see the “Commands” manual [13] and section "SHOW-DEVICE-CONFIGURATION (Display system configuration and availability)".

The home pubset must be assigned explicitly and exclusively to the VM before the guest system is started).

Implicit pubset assignment is not available for pubsets which should already be imported when the guest system starts up.

Implicit pubset assignment

The BS2000 command /ATTACH-DEVICE UNIT=*PUBSET-DEVICES(...) assigns all pubset devices to the VM implicitly without a mnemonic device name needing to be specified. At the same time the command attaches the pubset devices in the guest system.

Usage mode in the case of implicit device assignment:

• Pubset devices are assigned for shared use (usage mode SHARED).

• Pubset devices which are already assigned exclusively to another VM cannot be assigned implicitly.

Implicit release of pubsets

The BS2000 command /DETACH-DEVICE UNIT=*PUBSET-DEVICES(...) releases all devices of the pubset; they are removed from the VM.

The following points are worth noting about the implicit release of devices:

• Pubsets assigned to a VM implicitly are released when the guest system is shut down or when /RESET-VM, /DELETE-VM or /START-VM (normal IPL) is issued for the relevant VM.

• In the following cases implicitly assigned pubset devices remain with the VM for diagnostic reasons:

  • abnormal system termination in the guest system

  • system shutdown in the guest system with automatic SLED, e.g. in the case of automatic restart and the restart option DUMP=*SLED

  • /START-VM ...,DIAGNOSTIC-IPL=*YES for the VM

  Exclusive use is changed to shared use. Other, implicitly assigned devices are released.